1. Field of the Invention
The present invention is in the field of medical instruments and more particularly, relates to a device for obtaining a culture sample from a particular portion of a body passage, while avoiding contamination of the sample from other portions of the passage.
2. The Prior Art
Although the device of the present invention can be used effectively in obtaining a sample from any of several body passages, the device was developed originally in response to the need for a better way of obtaining samples from the trachea and/or bronchial areas while avoiding contamination of the sample by organisms in the mouth.
Heretofore, such samples were obtained by surgical penetration into the trachea. An incision was made in the neck of the patient and a hollow-bore needle was inserted into the trachea. Next, a catheter was passed through the hollow needle and into the trachea. Thereafter, a sample of the secretion was aspirated through the catheter. Although this procedure bypasses the patient's mouth, and avoids mouth contaminants, it was, nevertheless, a specialty procedure, relatively expensive to perform and carrying bleeding complications, discomfort to the patient, and risk of penetration to surrounding structures.
The problem of obtaining uncontaminated samples is well-known, and a number of different approaches to the problem have been suggested. The known approaches all require relatively complicated rigid structures which entail some risk of sample contamination.
In U.S. Pat. No. 3,037,496, issued June 5, 1962, Melges discloses a fertility testing apparatus, including three telescoping tubes and a rupturable closure at the distal end. Extension of the testing element beyond the contaminated distal end of the tube is limited, and accordingly, contamination of the sample at the end of the tube is possible.
In U.S. Pat. No. 3,513,830, issued May 26, 1970 to Kalayjian, there is shown an instrument for obtaining body cultures in which a tube is closed at the distal end by a cap which is opened by pushing from within the tube, and once the cap has been opened, the sample-taking surface is extended through the open distal end of the tube. Because the cap is contaminated, it is possible for the sampling swab to become contaminated as it is extended past the cap.
The devices shown in U.S. Pat. No. 3,394,699, issued July 10, 1968 to Koett and in U.S. Pat. No. 3,438,366, issued Apr. 15, 1969 to Kariher et al., employ similar arrangements at the distal end of the device for reducing contamination of the sample. In these devices, an inner rod includes a sealing knob which fits into the distal end of the tube to seal it to prevent contamination of the sample-gathering surface which is located on the central rod adjacent the knob at its end. During insertion, the knob becomes contaminated, and the same motion which exposes the sampling surface also smears the contaminated material on the knob along the area to be sampled, thereby contaminating the area.
In U.S. Pat. No. 3,017,879, issued Jan. 23, 1962 to Sapit et al., there is shown a fertility tester in which the sampling tip is extended through a hole at the end of the tube after the tube has been put in place. This device, like the Melges device discussed above, has no provision for preventing contamination of the sampling material by the contaminated distal end of the tube.
In U.S. Pat. No. 4,023,559, issued May 17, 1977 to Gaskell there is shown a sampling device in which the swab is surrounded by two telescoped tubes. After the device has been placed in position, the inner tube which encloses the swab is pushed through the distal end of the outer tube which has been cut to form segments which normally close the end of the outer tube, but which are resiliently displaceable by the inner tube. The inner tube is then extended through the distal end of the outer tube, and finally, the swab is extended beyond the distal end of the inner tube. Although this device is an improvement over previous devices, there is still a reduced risk of contamination. The device must necessarily be relatively rigid, and therefore may not be suitable for use in certain body passages.
Thus, the amount of effort expended by previous workers in the field indicates the importance of the problem and suggests that the ideal solution has not yet been found.